Does anything obvious stand out for you in terms of missing dependencies? I am rather new to ubuntu/linux. I can understand if you don't want to get into this. I will go to ppl website and look through their support files as well.

Thank you very much. Following your instructions, I have indeed been able to run ppl_lcdd from the bin folder and link it to test2.txt file you shared.

Yes, gawrilow was also right. I had to do sudo make install.

I obtain an output that lists:

414 40 integer
<<and equations?>>

Is there a way to correlate these coefficients with the variables of the cplex lp file of the OP? In other words, is there an easy way to interpret the ppl output ?

That is, could you let me know in what order did you populate the variables in your test2.txt file and meaning of other entries in that file? Then, if I understand the correlation between test2.txt file and ppl output, I can write some wrapper code around this that spits out the equations/inequalities in human understandable form.

Is there a way to correlate these coefficients with the variables of the cplex lp file of the OP? In other words, is there an easy way to interpret the ppl output ?

That is, could you let me know in what order did you populate the variables in your test2.txt file and meaning of other entries in that file? Then, if I understand the correlation between test2.txt file and ppl output, I can write some wrapper code around this that spits out the equations/inequalities in human understandable form.

I did this in the order that my own reader uses. If I remember correctly, it uses the order from the "BOUNDS" section, if provided. In your case, I recommend writing the file on your own. Then you know the order. But for production, I would not write such I file at all. I would use the API. As I said, I just did a test whether it works at all.

Concerning the other entries of the file, I just copied one example. It seems important to add a "1" as first element of each row. Didn't investigate this any further.

I created a lp2polyfloat.sh file to automate the task of reading in an LP file and computing the facets "quickly" by using Floats instead of Rationals as suggested earlier in this thread. The script file content is:

Could you let me know what I am doing wrong? On line 4, having Rational in place of Float does not give any error.

Also, is every occurrence of $p->LATTICE_POINTS "costly" in that is the computation of the lattice points done all over again at each place in the code where this occurs? For e.g., in the script above, I have that occurring at 3 places. Are the lattice points computed 3 times from scratch each time?

help 'LATTICE_POINTS';
polytope/objects/Polytope/methods/Lattice points in polytopes/LATTICE_POINTS:
LATTICE_POINTS() -> Matrix<Integer>
Only defined for Polytope<Rational>.
Returns the lattice points in bounded Polytopes.

The restriction is deliberate and justified: having imprecise coordinates, one would risk to deliver a lattice point lying outside the polyhedron, which would constitute an invalid result.

Also, is every occurrence of $p->LATTICE_POINTS "costly" in that is the computation of the lattice points done all over again at each place in the code where this occurs? For e.g., in the script above, I have that occurring at 3 places. Are the lattice points computed 3 times from scratch each time?

In general, polymake stores any computed property with the object, so that every subsequent access operation is as cheap as a lookup in a small hash table with few dozens entries. LATTICE_POINTS is a very thin wrapper function retrieving the first data member of the LATTICE_POINTS_GENERATOR property. It can safely be assumed as cheap.